Guest Post by Willis Eschenbach
Today I came across an IPCC figure (AR4 Working Group 1 Chapter 2, PDF, p. 208) that I hadn’t noticed before. I’m interested in the forcings and responses of the climate models. This one showed the forcings, both at the surface and at the top-of-atmosphere (TOA), from the Japanese MIROC climate model hindcast of the 20th century climate.
Now, do you notice some oddities in these two figures? Here’s what caught my eye.
The first oddity I noticed was that the surface forcing from the long-lived greenhouse gases (LLGHG) was so small compared to the top-of-atmosphere LLGHG radiative forcing. At the end of the record, the TOA forcing from LLGHG was just over two watts per square metre (W m-2). The surface forcing from LLGHG, on the other hand, was only about 0.45 W m-2. I don’t understand that.
This inspired me to actually digitize and measure the surface vs TOA radiation for a few of the components. For each W m-2 of TOA radiative forcing from a given source, the corresponding surface forcing was as follows:
Aerosol Direct: up to 15 W m-2 (variable)
Land Use: 1.5 W m-2
Volcanic Eruptions: 0.76 W m-2
Solar: 0.72 W m-2
Cloud Albedo: 0.67 W m-2
LLGHG: 0.21 W m-2
With the exception of the Aerosol Direct these relationships were stable throughout the record.
I have no idea why in their model e.g. one W m-2 of TOA solar forcing has more than three times the effect on the surface as one watt of TOA greenhouse gas forcing. All suggestions welcome.
The next oddity was that the sum of the radiative forcings for “LLGHG+Ozone+Aerosols+LandUse” is positive, about 1.4 W m-2. The surface forcing for the same combination, on the other hand, was strongly negative, at about -1.4 W/m2. The difference seems to be in the Aerosol Direct figures. It seems they are saying the aerosols make little difference to the TOA forcings but a large difference to the surface forcings … which seems possible, but if so, why would “Land Use” not show the same discrepancy between surface and TOA forcing? Wouldn’t a change in land use change the surface forcing more than the TOA forcing? But we don’t see that in the record.
In addition, the TOA Aerosol Direct radiative forcing changes very little during the period 1950-2000, while the corresponding surface forcing changes greatly. How can one change and not the other?
The next (although perhaps not the last) oddity was that the total surface forcing (excepting the sporadic volcanic contribution) generally decreased 1850-2000, with the total forcing (including volcanic) at the end of the period being -1.3 W m2, and the total forcing in 1950 being -0.6 W m-2 … why would the total surface forcing decrease over the period during which the temperature was generally rising? I thought perhaps the sign of the forcing for the surface was the reverse of that for the TOA forcings, but a quick examination of the corresponding volcanic forcings shows that the signs are the same. So the mystery persists.
In any case, those are the strangenesses that I found. Anyone with ideas about why any of those oddities are there is welcome to present them. What am I missing here? There’s some part of this I’m not getting.
In puzzlement,
w.
PS – I’m in total confusion regarding the albedo forcings that go all the way back to 1850 … if I were a suspicious man, I might think they just picked numbers to make their output match the historical record. Do we have the slightest scrap of evidence that the albedo changed in that manner during that time? Because I know of none.
PPS – Does anyone know of an online source for the surface and TOA forcing data in those figures?
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Willis
I also had been examining this graph and had at first been confused by the labels!
Chapter 2.2. of IPCC AR4 Working Group 1 report says:
“This chapter also uses the term ‘surface forcing’ to refer to the instantaneous perturbation of the surface radiative balance by a forcing agent. Surface forcing has quite different properties than RF and should not be used to compare forcing agents.” (RF being radiative forcing)
PS May I ask what graph digitisation software you used? The one I tried was more bother than it was worth and I ended up digitising parts of the RF graph manually!
Re post at Judith Curry’s site?
The largest forcing would, in my opinion, be SST combined with equatorial wind direction. In a word, El Nino. Which part of the model is a measure of the El Nino forcing on land temperature trend? El Nino (and the lack thereof) plays havoc with mathematical constructions of all these other parameters, and has by far, the greater energy potential.
For that matter, any other warm or cool ocean basin oscillation would also force land temperature changes. And we all know that long wave radiation from GHG under ideal conditions (calm surface) cannot affect SST’s to any degree worth putting into a model (the very weak signal from the skin only warmed surface could be safely ignored). And longwave heating of land air goes away at night (nocturnal radiative cooling) so we can ignore that too.
So we are talking about whether or not the sea surface is peeling back its layer of naturally warmed by the Sun surface, or is being silently still soaking up the shortwave IR deep into its upper layer, to be carried along the major currents, setting up on-shore weather systems that warm or cool the land.
To me, the secret force is in which way the wind blows over the sea.
It seems clear to me from the IPCC text accompanying Fig 2.23 that the labels on the figure are correct, so the caption is wrong.
The co-ordinating lead authors (i.e. they chose the content) for that chapter of FAR (Ch 3, ‘Changes in Atmospheric Constituents and in Radiative Forcing’) were P Forster (University of Leeds, UK) and V Ramaswamy (NOAA, USA).
Paul Maynard says:
June 5, 2011 at 2:29 am
Albedo at the poles makes little difference as there’s very little insolation in the first place. In the second place the ocean has an albedo near zero when the insolation is perpendicular to the surface but increases drastically as the rays move closer to parallel.
What makes a big difference is the variable sea ice extend in the arctic. Ice insulates the surface of the ocean. Where there is no ice cover the ocean can vent heat to space rapidly but when there is ice covering the surface it cannot. Thus arctic sea ice works opposite to the way ice works at lower latitudes. Less ice results in global cooling because the arctic “radiator” (it functions much the same as a radiator in an automobile with warm water from the tropics releasing heat when it circulates up to the poles via the oceanic conveyor belt) becomes more efficient. At lower latitudes where the sun’s rays are not nearly so oblique the albedo difference between ice or no ice is the dominant influence.
Jer0me says:
June 5, 2011 at 3:39 am
“There is also the inconvenient fact that as the ice melts, the sea itself, which is pretty much always warmer than the ice, is no longer insulated and can radiate heat to be lost to space. Indeed, that could even make a low sea ice coverage (esp the Arctic), a negative feedback.”
Correct. Glad to see others here can work through it.
Jer0me says:
June 5, 2011 at 3:39 am
“There is also the inconvenient fact that as the ice melts, the sea itself, which is pretty much always warmer than the ice, is no longer insulated and can radiate heat to be lost to space. Indeed, that could even make a low sea ice coverage (esp the Arctic), a negative feedback.”
Another factor is that low angle radiation — and most solar radiation in the Arctic is going to be low angle — seems to be mostly reflected by water, not absorbed. To test this, the next time you come to a puddle/pool/lake, focus on a spot on the water more than a few body lengths in front of you. What you will almost certainly see is a reflection of what is on the other side of the water. Observe how close you have to get before objects/markings on the bottom start to be visible through the reflected light. Of course if the water is rough, the angles will be more favorable for absorbtion part of the time. But I still think that the amount of solar absorbtion by artic sea water may be being overestimated.
You couldn’t make it up! Oh, well, uhm, hmmm, I suppose they just did, actually. Clang.
Willis writes:
“PS – I’m in total confusion regarding the albedo forcings that go all the way back to 1850 … if I were a suspicious man, I might think they just picked numbers to make their output match the historical record. Do we have the slightest scrap of evidence that the albedo changed in that manner during that time? Because I know of none.”
Willis, I am surprised at you! Have you not learned that Earth existed in a Golden Age until the 1960s when hippies realized that capitalists had undertaken a plan to destroy it. This plan was exposed on the first Earth Day in 1970 and hippies such as James Hansen have made heroic efforts since then to end capitalism. So, Earth’s albedo was constant and perfect until 1970. /sarc
What the authors have proved is that they now own a supercomputer, or a timeshare, and they have figured out how to get a standard climate model to solve. Why they would publish this fact is a mystery.
JerOme reckons
__________
itself, which is pretty much always warmer than the ice,
__________
and what do you think the temperature of the water under the ice is Jerome?
I bet you, based on some well known physics, that it’s the same temperature as the ice.
I hit a wall trying to find anything to match forcings on aerosols. I think there might be evidence for volcanoes, but many of these values have “hockey stick” written all over them, especially aerosols. If you look at the various charts, it seems that some are just fudge factors used to make the total of all others with CO2 forcing come out to the “correct” value. Unfortunately, even the “correct” value of forcing is not cooperating, so I suspect aerosols will take the blame (China’s coal plants are spewing too much SO2 and making it cooler, and once they install scrubbers, we’ll all roast to death in a fiery armageddon created directly from the sins of our carbon footprint, (send money) blah, blah).
If you look at the surface forcing, it goes with the negative of population (approx), but actual forcing should have been vastly worse in the 1960’s and 1970’s, should have leveled off or decreased (when we started scrubbing and reducing automotive smog, which indeed made a huge difference), then started increasing again with industrialization of China and India. Instead it is smooth, which I doubt.
I don’t see any evidence for highly negative aerosol forcing at all, it gets washed out too fast in the atmosphere, though persistently high emissions would support a somewhat higher level. Rather, it is merely a convenient scapegoat propping up the theory of high CO2 forcing and high sensitivity. In other words, if you reduce CO2 forcing to a reasonable level (that has some correspondence to reality), you don’t NEED to have an offsetting aerosol fudge factor to make the observed temperatures fit a model.
I’ve had a hard time finding sources, but I see from the report where I can look next. If you find any good data, please post a link.
Oops, now I see why there is no data. From page 208:
Determining the time series for aerosol and ozone RF is far
more difficult because of uncertainties in the knowledge of past
emissions and chemical-microphysical modelling. Several time
series for these and other RFs have been constructed (e.g., Myhre
et al., 2001; Ramaswamy et al., 2001; Hansen et al., 2002).
General Circulation Models develop their own time evolution
of many forcings based on the temporal history of the relevant
concentrations. As an example, the temporal evolution of the
global and annual mean, instantaneous, all-sky RF and surface
forcing due to the principal agents simulated by the Model for
Interdisciplinary Research on Climate (MIROC) + Spectral
Radiation-Transport Model for Aerosol Species (SPRINTARS)
GCM (Nozawa et al., 2005; Takemura et al., 2005) is illustrated
in Figure 2.23. Although there are differences between models
with regards to the temporal reconstructions and thus presentday
forcing estimates, they typically have a qualitatively similar
temporal evolution since they often base the temporal histories
on similar emissions data.”
Translation: It was model generated. Excellent! Sure saves a lot of time and instrumentation that way. Certainly it’s a far more robust way to get what you want…
I’d love to see the article “First Light on the Aerosol Hockeystick”… Once again, great stuff, Willis… Thanks.
http://wattsupwiththat.com/2011/05/09/first-light-on-the-ozone-hockeystick/
(Michael D Smith says:
May 9, 2011 at 5:50 pm
Just wait until you get to aerosols…)
I’m not sure why but looking at the graphs makes me feel rather cold.
I noticed that the simulation stopped in 2000.
I wonder how it matched the lack of warming from 1998 to the present. With the high simulated GHG warming how does it account for the lack of warming ?
The simulation must fail miserably from 1998 to present.
“The model is then run varying the guessed values until the output appears to match the real world.”
Almost, but not true in fact. The models are run and the parameters varied until the models match what the experimenters believe to be the real world. Thus, any results that do not match what the experimenters believe to be true will be rejected, even if in fact they are true physically. As well, any results that match what the experimenters believe to be true will be incorporated into the models, even if in fact they are physically impossible.
This has long been recognized in medicine and other sciences and has resulted in double blind testing to eliminate contamination of the results by experimenter bias. Climate Science has not done this and as a result the models cannot be assumed to be modelling the real world. It is much more likely that the models are in fact simply modelling the experimenter’s belief about climate.
This same process is also true of the IPCC report. The report is not assembled using experimental controls. Rather it is assembled to match what the authors and governments believe to be true. Data that does not match there beliefs is rejected, and data that matches these beliefs is included, even if the source can clearly be shown to be no more than propaganda, with no basis in fact.
Thus the increasing reliance of the IPCC on non peer reviewed material and the recent policy announcement by the IPCC that they would not flag non peer reviewed material in the report, because it would be “too much work.” This policy directly contradicts the instructions given to the IPCC in the last review. As such, a more likely explanation is that the IPCC will not flag non peer reviewed material because they know it would weaken the case for AGW in the IPCC’s next report.
Hans Erren says:
June 5, 2011 at 3:16 am
Thanks, Hans.
w.
P. Solar says:
June 5, 2011 at 3:23 am
Thank you, Mr. Solar … you are of course right.
w.
Artr says:
June 5, 2011 at 5:56 am
Yes. The albedo near the poles is often high for a variety of reasons, and when that is so, a change to ice makes little difference.
w.
NicL_UK says:
June 5, 2011 at 6:01 am
I use a program called GraphClick (for the Mac, don’t know if they have a PC version). Works great.
w.
Following the link from Hans Erren above, the only thing I could find was the Hadley Centre publication, “Radiative forcing by anthropogenic surface albedo change from 1750 to 1990”.
But that didn’t help, as it was only surface albedo, not cloud albedo. So I’m still in mystery as to the provenance of the cloud albedo.
w.
Concerining oddities, the CSU sea level page writes this:
” How often are the global mean sea level estimates updated?
We update the sea level data approximately bimonthly (every two months). The altimeter data are released by NASA/CNES as a 10-day group of files corresponding to the satellite track repeat cycle (10 days). There is also a two-month delay between the time the data are collected on the satellite to their final product generation (known as a final geophysical data record (GDR)). ”
Why is it their sea levels haven’t been updated since January?
Paul Maynard says:
June 5, 2011 at 2:29 am
Albedo
I have what might be a dumb question on albedo at the Arctic. A standard MMGW feedback argument is that with warming, the ice melts causing a change in albedo and so more warming as less incoming HF radiation is reflected back space.
Yet I remember from my O level physics that we regard the suns ray as travelling in parallel lines. If that is true, the surface at the Arctic is virtually parallel to the rays and thus they pass through the atmosphere with very limited opportunity to melt the ice.
—-
Paul, your statement would agree with what NASA via MODIS (I think) that albedo does not change meaningfully whether there is ice or not in the arctic. NASA was surprised in the story. There is a NASA article on that but I have no idea where. I read it around last summer.
First, the paper “H. Shiogama, and S.A. Crooks, 2005: Detecting natural influence on surface air temperature change in the early twentieth century.” is available for download via GoogleScholar, but that doesn’t help much, because the paper just reported that they made a model, and doesn’t contain these time-evolution RF graphs…
…which are really interesting! When I first read AR4 I wondered why people weren’t making a bigger deal out of these time series. Also, take a look at spatial patterns of surface and TOA forcing! Weird…they say “Note that the spatial pattern of the forcing is not indicative of the climate response pattern.” presumably because surface temperatures are dependent on weather, not just surface heating; “It should be noted that a perturbation to the surface energy budget involves sensible and latent heat fluxes besides solar and longwave irradiance; therefore, it can quantitatively be very different from the RF, which is calculated at the tropopause, and thus is not representative of the energy balance perturbation to the surface-troposphere (climate) system. While the surface forcing adds to the overall description of the total perturbation brought about by an agent, the RF and surface forcing should not be directly compared nor should the surface forcing be considered in isolation for evaluating the climate response (see, e.g., the caveats expressed in Manabe and Wetherald, 1967; Ramanathan, 1981).”
Differences between the surface and TOA forcing are relevant to the predicted “tropospheric hotspot”. If the heat isn’t leaving the TOA and isn’t transmitted to the surface, it must be absorbed in the troposphere. Where’s the heat?
The AR4 is careful to surround these figures in caveats, but they seem to want to have it two ways: “…the location of maximum RF is rarely coincident with the location of maximum [climate, temperature] response (Boer and Yu, 2003b)…. Identification of different patterns of response is particularly important for attributing past climate change to particular mechanisms…”
Apologies in advance, my time to scan the comments was limited, so if this has been brought up before, then please excuse the redundancy:
I noticed right away this factor of “Cloud Albedo”, and there is one curve for LT (lower Troposphere) and one for TOA (Top of the Atmosphere).
I must be confused on what the ‘top of the atmosphere’ is; I was thinking that as an arbitrary figure, we might consider something between 100 and 200 km above the surface for the ‘top of the atmosphere’, since there is no “definable”, “demarcatible”, “fixed-in-time-and-space” ‘top of the atmosphere’.
So, whatever the ‘top of the atmosphere’ actually is, I was under the impression that there were, in fact, no clouds at all, by virtue of the fact that clouds are an LT and lower stratosphere phenomenon (when towering CB’s punch through the tropopause).
Call me confused, and/or misinformed!
Mark H.
Willis wrote:
“PS – I’m in total confusion regarding the albedo forcings that go all the way back to 1850 … if I were a suspicious man, I might think they just picked numbers to make their output match the historical record. Do we have the slightest scrap of evidence that the albedo changed in that manner during that time? Because I know of none.”
I’d side with the theory they made the numbers up. From 1850? Give me a break. I have an atlas that was published in 1880 that has the middle of Africa labeled “unknown interior”. Most of the surface of the planet wasn’t monitored the way it can be today. Before 1957 there were no satellites to measure cloud cover or ice extent. The reason you know of no historical record is most likely because there is none. The someone who provided the data needs to show where it came from.
Last, there is no “if” about it. You are a suspicious man. 🙂 With lots of good reasons to be. Its the scientific way.
Mark H.
Google is your friend.
http://mynasadata.larc.nasa.gov/glossary.php?&letter=T